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Curved cranks


stewie911
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I can't see how these can make you go faster at all. If anything you will probably go slower due to the actual crank arm being longer than what is needed.

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Will have exactly the same effect as a straight crank excepting a little less stiff and heavier due to the stupid shape.

 

Anyway - good luck to the inventors of this.

 

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Like Gumpole says, it's a load of crock. What difference does it make how many kinks and curves are in the arms. The two arms are sill 180? to each other.

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All that the curved crank does is add weight and flex.

 

I know that they try to say that you move the pedal forward of the 'dead spot', but the reality is that the 'dead spot' will be wherever the pedal is directly above the BB.

 

The shape of the crank is completely irrelevant, except to say that the stiffer it is, the more power it will transfer, and it will be stiffer if it is straight.

 

 

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So long as we keep pedalling in circles, dead spots are always going to be in in the same place, regardless of the crank shape: basic first year (matric?) mechanics.

 

Some questions to help the sceptics:

1.) Why doesn't their test report list their methodology? How was their crank angle measured?

2.) Why do they feel the need to make the report look longer than it really  is be including every page twice Tongue?

 

Spurious marketing claims aside, the cranks do look rather funky. I reckon a slightly more restrained curve would look quite interesting together with the wavy fork and stay on a Pinarello.

 

Edman2010-03-24 01:54:55

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I saw (cranks like) these at the Taipei cycle show last week at some "no name" stand. They where attached to some "hypermarket" bike. I understand the idea behind the design but really think it's trying to fix a problem that doesn't really exist.

 

Plus they look funny.

 

edit; put in (text).
Ghostface2010-03-24 02:25:50
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All that the curved crank does is add weight and flex.

 

I know that they try to say that you move the pedal forward of the 'dead spot'' date=' but the reality is that the 'dead spot' will be wherever the pedal is directly above the BB.

 

The shape of the crank is completely irrelevant, except to say that the stiffer it is, the more power it will transfer, and it will be stiffer if it is straight.

 

[/quote']

 

 

 

Actually the crank arm design is very relevant to the function of this crank.

 

 

 

I remember reading about these in Ride (or Bicycling) two years ago. They have a 30' (or something like that [EDIT: Acutely 10' forward float]) free movement when you hit the magical dead spot.

 

 

 

This crank really interested me as at that stage I was not yet cycling.

 

 

 

When I was still on platforms I was wondering if I should look these cranks up, then when I hit cleats I realised what a load of crap.cbrunsdon2010-03-24 03:17:10

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Draw a sraight line between the centr of the BB and the centre of the pedal axle and what do you get? A straight line! that's the line the force will follow, same as a standard crank...

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Obviously the torque stays the same. Force x Distance

 

Who has mechanical engineering software to run a simulation for us?
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Obviously the torque stays the same. Force x Distance

 

Who has mechanical engineering software to run a simulation for us?

 

No need, this is a complete joke. If I understand their report correctly, they applied a static load to the crank arm vertically downwards, and measured the corresponding output force on the other crank, I would assume at right angles to the output crank arm.  These figures are meaningless, as even if the output force was "increased by 30%" on paper, this means nothing as you are merely shifting the dead-spot to an earlier point. The virtual lever arm remains the same.

 

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